A friend found a tombstone porcelain sign that had Penn Pepper motor oil, 30 cents a quart on one side and had OLD GOLD OIL 25 CENTS A QUART ON THE OTHER SIDE. Can anybody tell me what the dates would be on this oil sign, I have never seen two diffrent oils on one sign Thanks for any help? Wish he would have took a picture but did not want to look to interested.SIGN IS ABOUT 24 X 18.